OpenSearch/rest-api-spec/api/ping.json

{
  "ping": {
    "documentation": "http://www.elasticsearch.org/guide/",
    "methods": ["HEAD"],
    "url": {
      "path": "/",
      "paths": ["/"],
      "parts": {
      },
      "params": {
      }
    },
    "body": null
  }
}